Brain shape as a biometric

ABSTRACT

The invention provides a method, system, and program product for identifying an individual using biometric data based on the individual&#39;s brain. In one embodiment, the invention includes constructing a biometric signature based on at least one of: features within a two-dimensional scan of the individual&#39;s brain and a difference in features between at least two two-dimensional scans of the individual&#39;s brain.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 11/405,330, filed 17 Apr. 2006, which is hereby incorporatedherein

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates generally to biometrics, and more particularly, toa method, system, and program product using brain shape as a biometric.

2. Background Art

The use of biometric data to identify individuals is known.Fingerprints, for example, have been used for over a century to identifyand distinguish individuals. More recently, biometric data have beenincluded in computerized databases, making such identifications quickerand, in general, more reliable.

The breadth of biometric data currently used in the identification ofindividuals has increased dramatically in recent years. Systems designedto identify individuals based on facial images, iris images, and otherphysical characteristics are now routinely used to limit access tosecure locations and to identify individuals.

For example, biometric data associated with persons authorized to accessto a secure location may be stored in a database and linked to an accesspoint. All persons wishing to enter the secure area must submit to acollection of biometric data at the access point, which is then comparedto the database of biometric data associated with individuals authorizedto access the secure location. If the collected biometric data do notmatch biometric data within the database, the individual is deniedaccess to the secure location.

Similarly, a database may be compiled of biometric data associated withindividuals who are being sought or tracked by a law enforcement agency.For example, a database of facial images of known criminals orterrorists may be linked to a system designed to capture facial imagesof individuals in public spaces, such as shopping centers and airports.In the event that a facial image is captured by such a system andmatches an image in a database containing facial images of knowncriminals or terrorists, a law enforcement agency may choose toapprehend or monitor the individual whose facial image was captured.

A significant shortcoming of most known biometric systems, however, isthat they rely on physical features that may be altered. Such alterationmay be made with the intent of mimicking the biometric of anotherindividual (e.g., someone who has been authorized to access a securearea) or of avoiding identification (i.e., obscuring one's own biometricto avoid it being matched to a biometric in a biometric database). Forexample, facial features may be easily altered by plastic surgery orobscured with a mask or prosthetic device. Iris images may becounterfeited with contact lenses or obscured with contact lenses orglasses. Even fingerprints may be counterfeited and are easily obscuredby gloves.

To this extent, a need exists for methods and systems for identifying anindividual that do not suffer from the defects above.

SUMMARY OF THE INVENTION

The invention provides a method, system, and program product foridentifying an individual using biometric data based on the individual'sbrain. In one embodiment, the invention includes constructing abiometric signature based on at least one of: features within atwo-dimensional scan of the individual's brain and a difference infeatures between at least two two-dimensional scans of the individual'sbrain.

A first aspect of the invention provides a method for identifying anindividual using biometric data, the method comprising: obtainingbiometric data associated with the brain of an individual using anon-invasive measurement technique; extracting characteristics from thebiometric data using a feature extraction technique; comparing theextracted characteristics with other characteristics, stored in adatabase, extracted from other biometric data; and determining whetherthe extracted characteristics match characteristics stored in thedatabase.

A second aspect of the invention provides a system for identifying anindividual using biometric data, the system comprising: a system forobtaining biometric data associated with the brain of an individualusing a non-invasive measurement technique; a system for extractingcharacteristics from the biometric data using a feature extractiontechnique; a system for comparing the extracted characteristics withother characteristics, stored in a database, extracted from otherbiometric data; and a system for determining whether the extractedcharacteristics match characteristics stored in the database.

A third aspect of the invention provides a program product stored on acomputer-readable medium, which when executed, attempts to identify anindividual using biometric data, the program product comprising: programcode for obtaining biometric data associated with the brain of anindividual using a non-invasive measurement technique; program code forextracting characteristics from the biometric data using a featureextraction technique; program code for comparing the extractedcharacteristics with other characteristics, stored in a database, fromother biometric data; and program code for determining whether theextracted characteristics match characteristics stored in the database.

A fourth aspect of the invention provides a method for deploying anapplication for identifying an individual using biometric data,comprising: providing a computer infrastructure being operable to:obtain biometric data associated with the brain of an individual using anon-invasive measurement technique; extract characteristics from thebiometric data using a feature extraction technique; compare theextracted characteristics with other characteristics, stored in adatabase, from other biometric data; and determine whether the extractedcharacteristics match characteristics stored in the database.

The illustrative aspects of the present invention are designed to solvethe problems herein described and other problems not discussed, whichare discoverable by a skilled artisan.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings that depict various embodiments of the invention, in which:

FIG. 1 shows an image of a human brain.

FIG. 2 shows an illustrative two-dimensional magnetic resonance imaging(MRI) scan of a human brain, suitable for use in practicing theinvention.

FIG. 3 shows illustrative two-dimensional MRI scans taken at differentdepths of a human brain, suitable for use in practicing the invention.

FIGS. 4A-C show an illustrative MRI scan of a brain and illustrativebiometric signatures derived therefrom.

FIG. 5 shows a flow diagram of an illustrative method according to theinvention.

FIG. 6 shows a block diagram of an illustrative system according to theinvention.

It is noted that the drawings of the invention are not to scale. Thedrawings are intended to depict only typical aspects of the invention,and therefore should not be considered as limiting the scope of theinvention. In the drawings, like numbering represents like elementsbetween the drawings.

DETAILED DESCRIPTION

As indicated above, the invention provides a method, system, and programproduct for identifying an individual using biometric data based on theindividual's brain. More particularly, the invention includes the use ofbiometric data related to the geometry of the individual's brain. Asused herein, brain geometry includes the overall shape of the brain as awhole, and surface and/or interior features of the brain (e.g., itstexture), and the location of functional regions based on brainactivity.

Biometric data derived from internal portions of the body are moredifficult to deliberately alter than are external portions of the body.Still, internally-derived biometrics are not free from alteration,whether deliberate or otherwise. Organ transplantation, cosmetic and/orreconstructive implantations, and skeletal alterations due to injuryand/or surgery all have the ability to alter a biometric derived frominternal portions of the body.

The structure of the brain, however, is not easily altered, as any suchalteration carries with it the risk of serious and permanent impairmentof an individual's ability to function or maintain basic bodilyfunctions. In addition, the detailed foldings of the cerebrum andcerebellum are relatively constant over an individual's lifetime and areepigenetic (i.e., the detailed folding is different between identicaltwins). Even physiological conditions, such as dehydration, anddegenerative disorders, such as Parkinson's Disease, while capable ofaltering the overall appearance of the brain's surface, do not alter thepresence or relative locations of the folds of the cerebrum orcerebellum. All of these characteristics make the structure of thebrain, in general, and the folding patterns of the cerebrum and/orcerebellum, in particular, ideal features for use as a biometric.

Just as geometric features of the brain make identification of anindividual inviolable, behavioral measurements obtained from the braincan also uniquely identify an individual. For example, in a restingstate, behavioral measurements computed from sensing variousdifferential metabolic activities in the brain, such as oxygen intake,blood flow, etc., cannot be altered consciously by an individual and cantherefore be used to identify an individual or distinguish oneindividual from another. These behavioral measurements can be obtainedby gathering functional magnetic resonance imaging (fMRI) sequences ofthe brain.

Further, behavioral measurements can also be obtained from the brain ofan individual in response to a particular stimulus such as showing animage to an individual and recording the brain activity occurring inresponse to this stimulus using fMRI sequences. Techniques such as fMRIcan determine the specific location of brain regions used in the visualprocessing of this stimulus, the memory retrieval of a similar priorobject, the selection of a linguistic name for the object, thegeneration of a response sentence, and the motor activation forarticulation of the spoken response. Brain biometrics can be based bothon the location and extents of the brain regions involved, and also thetemporal pattern of transitions between them as response generationprogresses. While it is conceivable that an individual may go to thelength of controlling their external body reaction to the stimulusshown, it is difficult or impossible to deliberately control the regionsof the brain activated by the stimulus or their timings.

Referring to FIG. 1, an illustration of an exterior surface of a humanbrain 100 is shown. The cerebrum 102 is shown comprising the frontallobe 110, the parietal lobe 120, the occipital lobe 130, and thetemporal lobe 140. Also shown are the cerebellum 160 and medullaoblongata 150.

Preferred features of the brain 100, from which biometric data useful inthe present invention may be derived, include the position, depth, andcurvature of sulci 124, 132 (i.e., superficial depressions of the greymatter) of the cerebrum 102 and folia 162 (i.e., laminated depressions)of the cerebellum 160. Often, the position, depth, and curvature of suchfeatures can be determined from a cross-sectional image of the brain, asmay be obtained using any known or later-developed imaging device,method, or system. Suitable non-invasive methods include, for example,X-Ray, magnetic resonance imaging (MRI), positron emission tomography(PET), and computerized axial tomography (CAT).

For example, FIG. 2 shows a two-dimensional MRI scan 200 of a crosssection of the brain along the X and Y axes. The frontal lobe 210,parietal lobe 220, and occipital lobe 230 are visible, as is the midbrain 270. Sulci 222, 224, 232 are visible in MRI scan 200, just as theyare visible along an exterior surface of the brain, as in FIG. 1.

A single two-dimensional scan, such as MRI scan 200, may be used as abiometric for an individual. For example, a biometric signature may bederived from features of MRI scan 200. By way of example, a distance maybe determined between a feature of mid brain 270 (e.g., its center) andsulcus 232. Preferably, a plurality of such distances is determined(e.g., between mid brain 270 and sulcus 222; between mid brain 270 andsulcus 224; between sulcus 222 and sulcus 224; etc.) and a biometricsignature derived therefrom. Methods for the derivation of suchsignatures are known, particularly within the field of biometrics.Accordingly, any known or later-developed method for deriving abiometric signature may be used.

In particular, a biometric may be formed using the depth of each sulcus(or fissure) relative to the exterior brain (or lobe) surface, and itsposition relative to an anatomical coordinate system based on theposition of the center of the mid-brain 270 and the central dividingfissure. Other coordinate systems, such as Talairach space based on theanterior and posterior commissures, may also be used. Thiscanonicalization process helps transform data obtained at differenttimes into representations in a standard brain-based coordinate frame sothat they can be compared (as opposed to just recording the raw imagecoordinates of each feature).

In addition to local geometric features, such as the sulci, globalgeometric characteristics may also be used to form biometric signatures.Such characteristics include the overall volume of the brain, its lengthto width ratio, its left-right asymmetry, and the fractal dimension ofthe surface (perimeter squared versus area in two dimensions).

To ensure that a two-dimensional scan of an individual's brain taken atone time will match a similar scan taken at another time, it helps tomake sure the plane of each scan is registered with respect to theoverall brain in the same way. This registration might be accomplished,for example, by aligning the scanning equipment with respect to easilyobservable external features of the individual. In a preferredembodiment, registration is performed by aligning the two-dimensionalscanner in the plane that contains the individual's ear canals and themidpoint between the eye sockets. While certain skull features can bereshaped with plastic surgery, the location of these perceptual orificesis difficult and dangerous to alter.

In a preferred embodiment, the invention comprises the derivation of abiometric signature from features of a plurality of images of the brain,such as MRI scan 200. That is, a preferred method includes obtaining aplurality of images of the brain, preferably at varying imaging depthsthrough the brain, and deriving a “three-dimensional” biometricsignature therefrom.

For example, in FIG. 3, a plurality of two-dimensional MRI scans 200,300, 400 taken at varying depths through the brain is shown. Asdescribed above, a biometric signature may be derived using features ofeach MRI scan individually. There are well-known techniques forreassembling such slices into a three-dimensional model of the brain'ssurface and its interior. From these three-dimensional models, viewssuch as that shown in FIG. 1 may be obtained. Such a three-dimensionalmodel provides much more information about the geometry of the brain,particularly the folding pattern in the cerebrum 102 and cerebellum 160.

In a three-dimensional model, the orthogonal depth of a fold (such as132 in FIG. 1) relative to the surface may be measured more accurately.Moreover, the position of such a feature may be recorded with moredetail (e.g. {r, theta} in a two-dimensional model versus {r, theta,phi} in a three-dimensional model). As with the two-dimensional cases,the choice of a canonical coordinate system for representing thesecoordinates may be based on anatomical features detected in the data.These include overall features of the brain, such as its moments ofinertia, as well as the positions and orientations of certain easilyobserved internal features such as the commissures, medulla oblongata,lateral geniculate body, etc.

The branching pattern of the sulci may also be recorded as a biometric.For example, a graph of bifurcation nodes along with the inter-nodedistances encodes the fold connectivity information for a particularbrain. FIG. 4A shows a three-dimensional surface model 500 computed froma plurality of two-dimensional slices. In three-dimensional model 500, anumber of sulci 530 have been traced with linear segments 531. In FIG.4B, the resulting graph model 550 consists of nodes 551 where severalsulci meet or one sulcus has a major turn, and links 552 which run alongthe individual sulci. Each link may optionally be parameterized with itslength and/or angle. Similarly, each node may optionally beparameterized by its three-dimensional position and/or its offset fromother nodes in graph 550.

Alternatively, the dual of this, the pattern of gyri between the sulcimay be recorded. This might be done by finding the medial axis of eachgyrus and segmenting this skeletonized representation at points of highcurvature. In FIG. 4A, the skeleton of selected gyri is shown as 520.The resulting semi-linear segments could be assembled into a graph 540,shown in FIG. 4C, augmented with the segment lengths 542 and join angles541, to represent the overall gyrus pattern for later matching.

As will be recognized by one skilled in the art, the use of biometricdata or a biometric signature to identify an individual requires thecomparison of obtained biometric data or a biometric signature derivedfrom such data to a database containing the biometric data or biometricsignatures of known origin. As such, the same or substantially the samemethods (e.g., scanning technology, biometric signature algorithm, etc.)must be used with respect to both the obtained biometric data orbiometric signature and the biometric data or biometric signaturesstored in the database.

Referring now to FIG. 5, a flow diagram of an illustrative methodaccording to the invention is shown. First, at step S1, biometric dataare obtained from an individual to be identified. As explained above,such data may be obtained using any number of methods, devices, orsystems, including, for example, an MRI device. Next, at optional stepS2, a biometric signature is derived from the biometric data obtained atstep S1. At step S3, one or both of the biometric data obtained at stepS1 and the biometric signature derived at step S2 are compared tobiometric data and/or biometric signatures stored in a database.

At step S4, it is determined whether the obtained biometric data and/orderived biometric signature match biometric data and/or biometricsignatures stored in the database. If a match is found, anidentification is declared at step S5. If a match is not found, noidentification is declared at step S6.

FIG. 6 shows an illustrative system 10 for identifying an individualusing biometric data based on the individual's brain. To this extent,system 10 includes a computer infrastructure 12 that can perform thevarious process steps described herein for identifying an individualusing biometric data based on the individual's brain. In particular,computer infrastructure 12 is shown including a computer system 14 thatcomprises a biometric system 40, which enables computer system 14 toidentify an individual using biometric data based on the individual'sbrain by performing the process steps of the invention.

Computer system 14 is shown including a processing unit 20, a memory 22,an input/output (I/O) interface 26, and a bus 24. Further, computersystem 14 is shown in communication with external devices 28 and astorage system 30. As is known in the art, in general, processing unit20 executes computer program code, such as biometric system 40, that isstored in memory 22 and/or storage system 30. While executing computerprogram code, processing unit 20 can read and/or write data from/tomemory 22, storage system 30, and/or I/O interface 26. Bus 24 provides acommunication link between each of the components in computer system 14.External devices 28 can comprise any device that enables a user (notshown) to interact with computer system 14 or any device that enablescomputer system 14 to communicate with one or more other computersystems.

In any event, computer system 14 can comprise any general purposecomputing article of manufacture capable of executing computer programcode installed by a user (e.g., a personal computer, server, handhelddevice, etc.). However, it is understood that computer system 14 andbiometric system 40 are only representative of various possible computersystems that may perform the various process steps of the invention. Tothis extent, in other embodiments, computer system 14 can comprise anyspecific purpose computing article of manufacture comprising hardwareand/or computer program code for performing specific functions, anycomputing article of manufacture that comprises a combination ofspecific purpose and general purpose hardware/software, or the like. Ineach case, the program code and hardware can be created using standardprogramming and engineering techniques, respectively.

Similarly, computer infrastructure 12 is only illustrative of varioustypes of computer infrastructures for implementing the invention. Forexample, in one embodiment, computer infrastructure 12 comprises two ormore computer systems (e.g., a server cluster) that communicate over anytype of wired and/or wireless communications link, such as a network, ashared memory, or the like, to perform the various process steps of theinvention. When the communications link comprises a network, the networkcan comprise any combination of one or more types of networks (e.g., theInternet, a wide area network, a local area network, a virtual privatenetwork, etc.). Regardless, communications between the computer systemsmay utilize any combination of various types of transmission techniques.

As previously mentioned, biometric system 40 enables computer system 14to identify an individual using biometric data based on the individual'sbrain. To this extent, biometric system 40 is shown including anobtaining system 42, which includes a scanning system 44, a signaturederiving system 46, and a comparing system 48. Operation of each ofthese systems is discussed above. Biometric system 40 may furtherinclude other system components 50 to provide additional or improvedfunctionality to biometric system 40. It is understood that some of thevarious systems shown in FIG. 6 can be implemented independently,combined, and/or stored in memory for one or more separate computersystems 14 that communicate over a network. Further, it is understoodthat some of the systems and/or functionality may not be implemented, oradditional systems and/or functionality may be included as part ofsystem 10.

While shown and described herein as a method and system for identifyingan individual using biometric data based on the individual's brain, itis understood that the invention further provides various alternativeembodiments. For example, in one embodiment, the invention provides acomputer-readable medium that includes computer program code to enable acomputer infrastructure to identify an individual using biometric databased on the individual's brain. To this extent, the computer-readablemedium includes program code, such as biometric system 40, thatimplements each of the various process steps of the invention. It isunderstood that the term “computer-readable medium” comprises one ormore of any type of physical embodiment of the program code. Inparticular, the computer-readable medium can comprise program codeembodied on one or more portable storage articles of manufacture (e.g.,a compact disc, a magnetic disk, a tape, etc.), on one or more datastorage portions of a computer system, such as memory 22 and/or storagesystem 30 (e.g., a fixed disk, a read-only memory, a random accessmemory, a cache memory, etc.), and/or as a data signal traveling over anetwork (e.g., during a wired/wireless electronic distribution of theprogram code).

In another embodiment, the invention provides a business method thatperforms the process steps of the invention on a subscription,advertising, and/or fee basis. That is, a service provider could offerto identify an individual using biometric data based on the individual'sbrain, as described above. In this case, the service provider cancreate, maintain, support, etc., a computer infrastructure, such ascomputer infrastructure 12, that performs the process steps of theinvention for one or more customers. In return, the service provider canreceive payment from the customer(s) under a subscription and/or feeagreement and/or the service provider can receive payment from the saleof advertising space to one or more third parties.

In still another embodiment, the invention provides a method ofgenerating a system for identifying an individual using biometric databased on the individual's brain. In this case, a computerinfrastructure, such as computer infrastructure 12, can be obtained(e.g., created, maintained, having made available to, etc.) and one ormore systems for performing the process steps of the invention can beobtained (e.g., created, purchased, used, modified, etc.) and deployedto the computer infrastructure. To this extent, the deployment of eachsystem can comprise one or more of (1) installing program code on acomputer system, such as computer system 14, from a computer-readablemedium; (2) adding one or more computer systems to the computerinfrastructure; and (3) incorporating and/or modifying one or moreexisting systems of the computer infrastructure, to enable the computerinfrastructure to perform the process steps of the invention.

As used herein, it is understood that the terms “program code” and“computer program code” are synonymous and mean any expression, in anylanguage, code or notation, of a set of instructions intended to cause acomputer system having an information processing capability to perform aparticular function either directly or after either or both of thefollowing: (a) conversion to another language, code or notation; and (b)reproduction in a different material form. To this extent, program codecan be embodied as one or more types of program products, such as anapplication/software program, component software/a library of functions,an operating system, a basic I/O system/driver for a particularcomputing and/or I/O device, and the like.

The foregoing description of various aspects of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and obviously, many modifications and variations arepossible. Such modifications and variations that may be apparent to aperson skilled in the art are intended to be included within the scopeof the invention as defined by the accompanying claims.

1. A method for identifying an individual using biometric data, themethod comprising: obtaining biometric data associated with the brain ofan individual using a non-invasive measurement technique; extractingcharacteristics from the biometric data using a feature extractiontechnique; comparing the extracted characteristics with othercharacteristics, stored in a database, extracted from other biometricdata; and determining whether the extracted characteristics matchcharacteristics stored in the database.
 2. The method of claim 1,wherein the biometric data includes geometric measurements.
 3. Themethod of claim 2, wherein the geometric measurements are based on afolding pattern of at least one of the following: the cerebrum and thecerebellum.
 4. The method of claim 3, wherein the geometric measurementsinclude at least one of the following: fold connectivity information andfold depths.
 5. The method of claim 2, wherein the geometricmeasurements are based on at least one of the following: atwo-dimensional image of the brain and a three-dimensional image of thebrain.
 6. The method of claim 5, further comprising: aligning thegeometric measurements in a standard coordinate frame using acanonicalization process.
 7. The method of claim 2, wherein the featureextraction technique computes at least one of the following: globalcharacteristics of the geometric measurements and local characteristicsof the geometric measurements.
 8. The method of claim 1, whereinobtaining includes obtaining the biometric data in a known coordinateframe using a registration technique.
 9. The method of claim 1, whereinthe biometric data includes behavioral measurements.
 10. The method ofclaim 9, wherein the behavioral measurements are based on differentialmetabolic activity.
 11. The method of claim 9, wherein the behavioralmeasurements are recorded in response to a stimulus.
 12. The method ofclaim 9, wherein the behavioral measurements are based on a changingpattern of region activations over time.
 13. A system for identifying anindividual using biometric data, the system comprising: a system forobtaining biometric data associated with the brain of an individualusing a non-invasive measurement technique; a system for extractingcharacteristics from the biometric data using a feature extractiontechnique; a system for comparing the extracted characteristics withother characteristics, stored in a database, extracted from otherbiometric data; and a system for determining whether the extractedcharacteristics match characteristics stored in the database.
 14. Thesystem of claim 13, wherein the biometric data includes geometricmeasurements based on a folding pattern of at least one of thefollowing: the cerebrum and the cerebellum.
 15. The system of claim 13,wherein the system for obtaining biometric data includes a system forobtaining the biometric data in a known coordinate frame using aregistration technique.
 16. The system of claim 13, wherein thebiometric data includes behavioral measurements based on differentialmetabolic activity.
 17. A program product stored on a computer-readablemedium, which when executed, attempts to identify an individual usingbiometric data, the program product comprising: program code forobtaining biometric data associated with the brain of an individualusing a non-invasive measurement technique; program code for extractingcharacteristics from the biometric data using a feature extractiontechnique; program code for comparing the extracted characteristics withother characteristics, stored in a database, from other biometric data;and program code for determining whether the extracted characteristicsmatch characteristics stored in the database.
 18. The program product ofclaim 17, wherein the biometric data includes geometric measurementsbased on a folding pattern of at least one of the following: thecerebrum and the cerebellum.
 19. The program product of claim 17,further comprising: program code for aligning the measurements in astandard coordinate frame using a canonicalization process.
 20. Theprogram product of claim 17, wherein the biometric data includesbehavioral measurements based on differential metabolic activity.
 21. Amethod for deploying an application for identifying an individual usingbiometric data, comprising: providing a computer infrastructure beingoperable to: obtain biometric data associated with the brain of anindividual using a non-invasive measurement technique; extractcharacteristics from the biometric data using a feature extractiontechnique; compare the extracted characteristics with othercharacteristics, stored in a database, from other biometric data; anddetermine whether the extracted characteristics match characteristicsstored in the database.